Internet protocol (IP) provides end-to-end datagram delivery service to protocols and applications and can use any link-layer technology that delivers packets. FIG. 1 illustrates the problem of emerging applications driving more functions to IP, expanding the “waist” of the hour glass. These emerging applications include email, www phone, simple mail transfer protocol (SMTP), hypertext transfer protocol (HTTP), real time protocol (RTP), transmission control protocol (TCP), user datagram protocol (UDP), and other protocols, which involve quality of service (QoS), multicast, mobility, security, virtual private network (VPN), and other features and are transported using Ethernet, point-to-point protocol (PPP), carrier sense multiple access (CSMA) asynchronous transfer mode (ATM), synchronous optical network (SONET), and other protocols over copper, fiber, radio, and other physical transport means. Conventional routers try to incorporate all of the new IP functions into routers, resulting in duplication of complex functions in multiple routers of a network. This also increases capital and operational expenses.
The demand for new features, such as VPN exceeds or will soon exceed the scalability allowed in conventional networks. Emerging applications, such as voice over IP (VOIP) and IP video are putting more stringent requirements (e.g., reliability) on conventional networks. There is a need for disaggregation of router hardware from router software using open, standards-based protocols for internetworking.